Background: Between 30 and 50% of colon tumors have mutations in the Kirsten-ras (KRAS) gene, which have a large nutritional attributable risk. Despite its high frequency in colorectal cancer (CRC), data to support specific associations between KRAS mutations in CRC and diet are sparse. Here, we conducted a systematic review to summarize the current epidemiological evidence on the association between various dietary factors and KRAS mutations. Methods: PubMed, Science Direct, and Cochrane databases were searched for relevant studies published until December 31, 2019, using inclusion and exclusion criteria in accordance with PRISMA guidelines. We analyzed the studies to find associations between nutritional factors and CRC tumors with KRAS mutations in humans. Results: We identified 28 relevant studies to include in this systematic review. In-depth analyses showed unclear associations between nutritional factors and KRAS mutations in CRC. Most epidemiological studies in the same nutrient or food often reported conflicting and/or inconclusive findings, whereas for some dietary factors, the results were homogeneous. Conclusions: Further research using a more robust prospective cohort study is needed to lend more credence to the epidemiological associations found between KRAS mutations and dietary factors.

Background: Colorectal cancer (CRC) has been reported as the third most commonly diagnosed cancer worldwide and is currently considered as a major public health concern. A peak increase in incidence has been noted in economically transitioning countries like Morocco where industrialization started shifting from a traditional lifestyle and diet toward a more westernized diet and lifestyle.Objective: This paper aims to present the protocol of a large-scale Moroccan case-control study that aims at investigating associations of diet, other lifestyle factors, and genetic traits with CRC risk in Morocco.Methods: A case-control study was conducted between 2009 and 2017, including 3032 case-control pairs (1516 cases and 1516 controls) matched on sex, age, and center in 5 major public health hospitals in Morocco. Questionnaires on sociodemographic data, lifestyle, family history of CRC, and nonsteroidal anti-inflammatory drugs (NSAIDs) were completed by trained investigators during face-to-face interviews. In addition, participants completed a semiquantitative food-frequency questionnaire, developed to assess food intake in the Moroccan population. Information regarding genetic factors was recorded for cases, and paraffin blocks (with embedded tumor tissues) are available in 3 collaborating hospitals. Conditional logistic regression analysis is planned to assess associations between diet and CRC risk. Binary logistic regression is considered to predict associations between mutations and nutritional risk factors including only CRC case series.Results: Altogether, 2966 cases-control pairs (1483 cases and 1483 controls) were considered eligible and included in this study. Both cases and controls did not differ significantly with respect to age (P=.36), sex (P=.51), center (P>.99), marital status (P=.30), and NSAID use (P=.08). However, participants in the control group were significantly more likely to have a high income level and live in urban areas and to have a high level of education than cases.Conclusions: This is the first study investigating potential risk factors of CRC such as lifestyle, diet, and genetic factors, originating from a southern Mediterranean country with low but increasing CRC prevalence. Identified risk factors allow the establishment of evidence-based preventive actions regarding nutrition and other lifestyle habits adapted to the Moroccan context. In brief, this study will promote cancer research and prevention in Morocco.International Registered Report Identifier (IRRID): RR1-10.2196/13998

Objectives: The current study aimed to develop a modified Mediterranean diet (MMD) score adjusted to the southern Mediterranean countries’ cultural specificities and to evaluate associations between adherence to this modified score and overweight/obesity risk in Moroccan adults.Design: Population-based cross-sectional study.Setting: Rural and urban areas of the five greatest provinces of Morocco.Participants: In total, 1516 participants were recruited between September 2009 and February 2017. Dietary assessment was obtained using a validated Moroccan FFQ. We constructed a MMD score focusing on twelve components. The MMD score ranged from 0 (no adherence to the traditional southern Mediterranean diet (MD)) to 12 (maximal adherence) and was categorised as low (scores 0–4), moderate (scores 5–7) and high (scores 8–12).Results: Among the whole population, 754 (50·5 %) were women and 738 (49·5 %) were men, and the mean age was about 55·60 ± 13·70. In total, 58 % of participants were moderately active. Regarding educational level, 50·7 % were illiterate. The prevalence of overweight and obesity was 43·3 and 8·6 %, respectively. In multivariate analyses, close adherence to MMD (scores 8–12) was associated with reduced overweight/obesity risk (OR 0·61, 95 % CI 0·44, 0·84).Conclusion: The prevalence of overweight and obesity was very high among Moroccan adults. Adherence to the traditional southern MD may help prevent overweight and obesity.